Apparatus for applying refractory covering to skid rail

ABSTRACT

The undersides of sections of horizontal pipes in heat treating furnaces are covered with refractory insulation material by a molding process. An air vibrator is used to agitate the refractory material mix as the mold is advanced toward the pipe. A liner is used to retain the mix against the pipe as it hardens, whereupon the rigid part of the mold may be immediately reused. The areas of the pipe left exposed are then covered in any suitable fashion such as by troweling. A mold assembly including an attached air vibrator and a liner is also disclosed.

United States Patent [1 1 Schaefer 1 APPARATUS FOR APPLYING REFRACTORY COVERING T0 SKID RAIL [76] Inventor: Frank W. Schaeier, 1678 Cory Dr.,

Dayton, Ohio 45406 [22] Filed: July 19, 1974 [21] App]. No.: 490,096

Related US. Application Data [62] Division of Ser. No. 260,372, June 7, 1972.

[451 Mar. 11, 1975 2,681,495 6/1954 Killian et al. 249/90 2,763,047 9/1956 Laster 249/90 3,606,633 9/1971 Engelmann 425/432 3,712,785 l/1973 Hirt et al. 425/425 Primary Examiner-J. Howard Flint, Jr. Attorney, Agent, or Firm--Dybvig & Dybvig [57] ABSTRACT A The undersides of sections of horizontal pipes in heat treating furnaces are covered with refractory insulation material by a molding process. An air vibrator is used to agitate the refractory material mix as the mold is advanced toward the pipe. A liner is used to retain the mix against the pipe as it hardens, whereupon the rigid part of the mold may be immediately reused. The areas of the pipe left exposed are then covered in any suitable fashion such as by troweling.

A mold assembly including an attached air vibrator and a liner is also disclosed.

3 Claims, 7 Drawing Figures All? V/Bl-PA TOR I PATENTED MRI 1 I975 JIE. 5

All? V/BHA TO J 6 V/BRA TOR APPARATUS FOR APPLYING REFRACTORY COVERING T SKID .RAIL This is a division of application Ser. No. 260,372, filed June 7, 1972.

BACKGROUND OF THE INVENTION This invention relates to a pipe insulation method and more particularly to the molding of castable refractory material to horizontal water cooled pipes for use in heat treating furnaces.

Several methods have been developed to provide insulation for water cooled pipes used in heat treating furnaces. For example, the following U.S. Pat. Nos. disclose such processes: 2,002,649; 2,436,452 and 2,693,352. Also pertinent to the general problem of applying coverings to pipes or the like are U.S. Pat. Nos. 2,150,830 and 3,020,618.

The known processes are not entirely satisfactory. Processes in which a refractory material mix is applied directly to the pipes and permitted to harden in place have not been generally used because of the difficulty in applying the refractory material to the undersides of the pipes. The use of molds has not been accepted, apparently because of the expense and long furnace down time required.

Until this invention, the preferred procedure for insulating the pipes involved the use of precast refractory material since precast material can be applied to the pipes in a relatively short time. However, precast material is quite expensive. Also, some difficulty has been encountered with the life of precast insulation, apparently due to the fact that an embedded wire mash is used to anchor the precast material and the wire mesh either provides an insufficient anchor or there is inadequate cooling of the wire mesh material since much of it is insulated from the water cooled pipe it surrounds.

SUMMARY OF THE INVENTION In accordance with this invention, cooling pipe can be insulated substantially as fast as it can be using precast materials. Suitable metal anchors areconnected to the pipe, the anchors thus being cooled and failures thereby minimized. A mixture of refractory material and water is loaded into a substantially semi-cylindrical mold assembly including a rigid form and an inexpensive, flexible liner on the inside face of the form. As the mold assembly is advanced toward a section of the pipe, the mix is agitated by a vibrator attached to the form. The anchors, therefore, do not impede the movement of the mold assembly toward the pipe. As soon as the mix is in intimate contact with the pipe, the vibration is stopped and the liner is secured to the pipe as by wires and the form removed so that the process may be repeated upon an adjacent section of the pipe. Thereafter the upper portion of the pipe may be insulated by troweling the refractory material thereon.

An inexpensive form suitable for use in the method may consist of a piece of sheet material formed as a semi-circular trough against which the liner is laid. End plates connected to the ends of the trough are provided, the end plates having axially aligned semicircular recesses with diameters matching the pipe diameters. An air vibrator can conveniently be attached to the center of the underside of the trough.

Utilizing the aforedescribed method and mold assembly two workmen can rapidly and efficiently cover a length of pipe with insulating material. Because liners are used to support the refractory material once it is in place on the pipe, there in only one form needed and the workmen are not delayed while waiting for the refractory material to harden.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a portion of pipe and a skid rail such as is common in heat treating furnaces. The portion of pipe in FIG. 1 is shown provided with anchoring studs.

FIG. 2 is a cross-sectional view of the pipe of FIG. I and a liner supporting refractory material covering approximately the lower half of the pipe.

FIG. 3 is a view similar to FIG. 2 but showing an alternate mode of attaching the liner to the pipe.

FIG. 4 is a view similar to FIG. 3 after insulating material has been troweled onto the upper portions of the pipe.

FIG. 5 is a side elevational view of the pipe of FIG. 4 shown partially insulated.

FIG. 6 is a side elevational view, with parts broken away and in cross section, of a form in accordance with this invention.

FIG. 7 is a transverse sectional view of the form of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIG. 1, a portion of a skid rail 10 is illustrated welded to the top of a horizontal pipe I4 through which coolant water is pumped. In order to anchor refractory material to the pipe 14, plural anchors in the form of headed studs 16 are welded to the out side of the pipe 14. The particular form of studs 16 is unimportant to this invention. For example, pairs of hook-like studs are commonly used for anchors and could be used for this purpose instead of the headed studs 16.

In accordance with this invention, the lower, approximate one-half of a section of the pipe 14 is first covered with a mixture of refractory material and water such as that illustrated at 18 in FIG. 2. While the refractory material is drying, thus hardening, it is supported by a sheet of cardboard or other flexible, inexpensive liner material 20 secured to the pipe 14 by one or more wire strands 22 extended around the pipe and over the top of the skid rail 10. As an alternative, which would be used whenever slabs or the like are supported by the skid rail 10 while the pipe 14 is being covered by re fractory material, the ends of the wire strands 22 may be twisted about conveniently accessible studs 16. Such mounting of the liner 20 is illustrated in FIG. 3.

The liner 20 must be sufficiently stiff to retain the mass of refractory material mix against the pipe 14 and in surrounding relation to the studs 16. Very stiff cardboard, however, is undesirable because it is heavy-and difficult to use in the molding or casting operation which will be described below. Ordinary cardboard or' the like material can easily be formed to the desired contour, that is the semi-circular shape illustrated. and because of the cohesive nature of the refractory mix cardboard is sufficient to support the mix after it is secured by the wires 22 to the pipe I4.

Mixtures of refractory material and water suitable for insulating pipes in heat treating furnaces are typically highly viscous and have a low slump similar to concrete mixes. The anchoring studs 16 are essential to retaining the refractory material after it hardens since the hardened material is quite brittle. Any form of anchor, however, presents a problem in that anchors act as abutments preventing the highly viscous refractory mix from being moved into engagement with the surface of the pipe.

The problem presented by the anchors blocking the application of the mix to the underside of the pipe is overcome by agitating the refractory mix as it is being applied. The liner 20 is located in a form 38 to produce a mold assembly. The form 38, which is described in detail below, is provided with a high speed vibrator 54. The mold assembly thus formed is loaded with the refractory mix. As the loaded mold assembly is advanced toward the pipe, the vibrator 54 is energized to agitate the mix. During such agitation or vibration of the mix, the cohesive nature of the mix is apparently so diminished that the form 38 loaded with the mix can be moved toward the pipe 14 during the period of vibration as if there were no anchoring studs 16. It is believed that the vibration or agitation may also hasten the hardening process because it tends to drive the water out of the mix. As soon as the mold assembly and the refractory mix are placed firmly against the pipe, the vibrator 54 is de-energized. The wires 22 are then secured to the pipe as previously described. As illustrated in the drawing, it is believed that the agitation of the mix averts the formation of air pockets which otherwise might form in the vicinity of the studs 16.

In practice, after refractory material has been applied to the underside of the first section of pipe 14 and the liner 20 fastened in place to the pipe, refractory material would be applied in the same manner to the underside of a second, adjacent section of pipe, the process being repeated until the refractory material has been applied to the underside along substantially the entire length of the pipe. A new liner is used for each section of pipe, the liner previously used being left in position to permit the mix of refractory material to harden in situ.

Thereafter the upper portions of the pipe 14 between the skid rail and the ledges, designated 18a, formed by the exposed upper ends of the molded refractory material 18 are covered with refractory material as indicated at 24 and 26 in FIG. 4. Preferably the portions of refractory material at 24 and 26 are simply troweled onto the portions of the pipe 14 uncovered by material 18.

FIG. 5 shows a length of pipe 14, sections of which have been completely insulated. One end of the pipe in FIG. 5 is shown uncovered so that the relationship of the insulating material to the pipe may'be better understood. As noted above, however, the preferred practice would be to first completely cover the lower half of the pipe before covering the upper half. In FIG. 5 it will be noted that the wires 2-2 and the liner 20 are left in place. These elements will usually be burned off when the heat treating furnace is in operation.

The middle section of the pipe 14 illustrated in FIG. 5 has been covered with refractory material in the manner described above. The adjacent section to the right in FIG. 5 is covered by supporting wire 30, a liner 28, and refractory mix 32, and refractory material supported, and hidden, by the liner 28. It will be noted that the two liners 20 and 28, and accordingly the refractory mix supported thereby, are separated by a gap 34. -A similar gap 36 is formed between the upper'portions of material 26 and 32. The gap 34 is formed by the form 38 used in applying the refractory material to the lower half of the pipe. The gap 36 may be formed by routing out the mix with the edge of a trowel. These gaps, which are aligned transversely of the pipe and between each section, serve as expansion gaps to prevent damage to the substantially inelastic, hardened refractory by permitting flexure of the pipe 14 which typically results from the weight of the slabs to be supported by the skid rails 10.

The form 38 illustrated in FIGS. 6 and 7 consists of an elongate open ended U-shaped trough 40, which determines the contour of the insulating covering and which is made from relatively rigid sheet material or the like having outwardly and longitudinally extending side flanges 42 along its upper edges. Connected to the ends of the trough are identical end plates 44 and 46. The upper margins of the end plates 44 and 46 have semi-circular recesses designated 48 and 50, respectively, which have substantially the same radius as the radius of the outside of the pipe to which the refractory material is to be applied. The spacing between the recesses 48,50 and the upper face of the trough 40 determine the depth or thickness of the refractory material to be applied to the pipe. Of course some allowance must be made for the liner 20 which is laid into the trough over wire strands 22 for the reasons already described.

The air vibrator 54 is connected, as by a clevis 52, to the center of the underside of the trough 40 for vibrating the form 38 and thus agitating the mix 18 as described above. The vibrator 54 must be capable of vibrating the substantial mass of the form 38 and the re fractory mix loaded therein at a relatively high vibrational speed. Air vibrators for this purpose are commercially available. For example, vibrators sold under Model AC, capable of operating at approximately 8,000 vibrations per minute are useful for this purpose and may be obtained from Cleveland Vibrator Company, 2,828 Clinton Avenue, Cleveland, Ohio 44113. Such vibrators come in various sizes. For a given application the size would depend upon the mass of the form and the refractory material mix. These factors are in turn dependent upon the diameter of the pipe and the depth of the insulating covering desired.

Any of various refractory compositions may be used in the practice of the process described above. High alumina refractory material such as a product sold under the trade designation Plicast 995 by the Plibrico Company, 1,800 Kingsbury Street, Chicago, Ill. 60614, is one usable material. The depth or thickness of the insulating layer applied by this process is not critical. A typical thickness would be 1-% inches on a 5 inch diameter pipe. Preferably the refractory insulation will be essentially the same depth as the length of the anchors and optionally may cover the anchors. The width of the gap 34 is determined by the thickness of the end plates 44,46. The width is optional; A; inch for l- /2 inch thick refractory is acceptable.

Although the presently preferred method and npparatus of this invention have been described, it will be understood that various changes may be made within the scope of the appended claims.

Having thus described my invention, I claim:

1. A mold assembly especially adapted to casting coverings to the undersides of horizontally oriented members having anchoring structures projecting therecomprises an air vibrator connected to the underside of said form at substantially its midpoint.

3. The improvement of claim 2 wherein said form comprises a substantially rigid sheet contoured to receive the cast material, end pieces connected to said last mentioned sheet, and means connecting said vibrator to said last mentioned sheet.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. I 3,870,M+2

DATED 1 March 11, 1975 INVENTOR(S) I Frank W. Schaefer It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, line 5, "the liner" should be ---a covering---.

Signed and Sealed this Third Day of August 1976 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN AIHsII'ng ()j'j'rcer (mnmisximzcr uj'Parenrs and Trademarks UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. ,8 0,44

DATED March 11, 1975 mvmroras) Frank w. Schaefer It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 1 "2,002,6 8" should be ---2,022,6 r9---. Column 1, line 32, "mash" should be ---mesh--. Column 2, line 2, "in" should be --is---.

Signed and sealed this 20th day of May 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks 

1. A mold assembly especially adapted to casting coverings to the undersides of horizontally oriented members having anchoring structures projecting therefrom, comprising a relatively rigid form having a surface contoured to the desired configuration of the cast material, a flexible sheet placed against said surface, means engaging said sheet for tying said sheet to the member on which the liner is to be cast, and vibrator means connected to said form for vibrating said form while advancing said assembly toward said member.
 1. A mold assembly especially adapted to casting coverings to the undersides of horizontally oriented members having anchoring structures projecting therefrom, comprising a relatively rigid form having a surface contoured to the desired configuration of the cast material, a flexible sheet placed against said surface, means engaging said sheet for tying said sheet to the member on which the liner is to be cast, and vibrator means connected to said form for vibrating said form while advancing said assembly toward said member.
 2. The assembly of claim 1 wherein said vibrator comprises an air vibrator connected to the underside of said form at substantially its midpoint. 